1.Soil-transmitted helminth infections among malaria patients determined by microscopy and real-time PCR methods at two district hospitals in Sarawak, Malaysia
Othman, N. ; Basuni, M. ; Miswan, N. ; Noordin, R.
Tropical Biomedicine 2015;32(4):710-716
Malaria is still endemic in Sarawak and Sabah. Numerous studies have indicated
that patients with malaria are commonly co-infected with helminthes particularly in endemic
regions. The aim of this study was to investigate the incidence of soil-transmitted helminth
(STH) infection among malaria patients using microscopy and multiplex real-time PCR at two
district hospitals in Sarawak. A total of 94 patients who were clinically-suspected to have
malaria were confirmed to be infected by both microscopy and multiplex real-time PCR. By
the molecular method, 23.4%, 74.5% and 2.1% of the samples were positive for Plasmodium
falciparum, P. vivax and mixed P. falciparum and P. vivax, respectively. Among the malaria
patients, 48.9% were found to be co-infected with STHs. In comparison, microscopic
examinations showed that 6.4% of the malaria patients were infected with STHs. From the
real-time PCR positive samples, 31.9% had single helminth infections while 17% had mixed
infections. In conclusion, this study showed that almost half of the malaria patients at the
two Sarawak hospitals were co-infected with helminth. Future studies should be specifically
designed to determine if there is any correlation between the two infections in terms of
incidence and intensity.
2.Optimal protein extraction methods from diverse sample types for protein profiling by using Two-Dimensional Electrophoresis (2DE)
Tan, A.A. ; Azman, S.N. ; Abdul Rani, N.R. ; Kua, B.C. ; Sasidharan, S. ; Kiew, L.V. ; Othman, N. ; Noordin, R. ; Chen, Y.*
Tropical Biomedicine 2011;28(3):620-629
There is a great diversity of protein samples types and origins, therefore the
optimal procedure for each sample type must be determined empirically. In order to obtain a
reproducible and complete sample presentation which view as many proteins as possible on
the desired 2DE gel, it is critical to perform additional sample preparation steps to improve
the quality of the final results, yet without selectively losing the proteins. To address this, we
developed a general method that is suitable for diverse sample types based on phenolchloroform
extraction method (represented by TRI reagent). This method was found to yield
good results when used to analyze human breast cancer cell line (MCF-7), Vibrio cholerae,
Cryptocaryon irritans cyst and liver abscess fat tissue. These types represent cell line,
bacteria, parasite cyst and pus respectively. For each type of samples, several attempts were
made to methodically compare protein isolation methods using TRI-reagent Kit, EasyBlue Kit,
PRO-PREPTM Protein Extraction Solution and lysis buffer. The most useful protocol allows the
extraction and separation of a wide diversity of protein samples that is reproducible among
repeated experiments. Our results demonstrated that the modified TRI-reagent Kit had the
highest protein yield as well as the greatest number of total proteins spots count for all type
of samples. Distinctive differences in spot patterns were also observed in the 2DE gel of
different extraction methods used for each type of sample.
3.Enhanced production of short-peptide tagged Ss3a recombinant protein as a novel potential biomarker for strongyloidiasis
Mohd-Hassan, N.H. ; Noordin, R. ; Arifin, N.
Tropical Biomedicine 2020;37(No.3):578-586
Strongyloidiasis is a mysterious yet important parasitic disease that is hard to diagnose. While microscopic examination remains a “controversial” gold standard method, improved diagnosis is achieved through confirmatory assays with serological and/or molecular diagnostic approaches. In the current serodiagnosis of strongyloidiasis, recombinant proteins have been adopted in place of the use of native parasite antigens, although the availability of diagnostically potential proteins are still limited. Here, we introduce a novel Strongyloides recombinant protein that is uniquely attached to two different short peptide tags as a potential diagnostic biomarker for serodiagnosis of strongyloidiasis, namely lysine (7K) and aspartic acid (7D). The work presented focus on improving the yield and purity of the previously unexpressed recombinant protein. Preliminary diagnostic evaluation of the recombinant favors Ss3a7K protein owing to its higher antigenicity performance with 80% sensitivity and 100% specificity, respectively.
4.Entamoeba infections and associated risk factors among migrant workers in Peninsular Malaysia
Sahimin, N. ; Yunus, M.H. ; Douadi, B. ; Yvonne Lim, A.L. ; Noordin, R. ; Behnke, J.M. ; Mohd Zain, S.N.
Tropical Biomedicine 2019;36(4):1014-1026
The influx of low skilled migrant workers to Malaysia from low socio-economic
countries where gastrointestinal parasitic infections are prevalent has raised concerns about
transmission to the local population. Three methods for detection (serology, microscopy and
molecular techniques) were utilized to identify Entamoeba infections amongst the targeted
cohort and determine risk factors associated with infection. Serological screening of 484
migrant workers from five working sectors in Peninsular Malaysia using IgG4 ELISA based on
the rPPDK antigen showed an overall seroprevalence of 7.4% (n = 36; CL95 = 5.3–10.1%) with
only one factor statistically associated with seropositivity of anti-amoebic antibodies, i.e.
years of residence in Malaysia (χ2
1 = 4.007, p = 0.045). Microscopic examination of 388 faecal
samples for protozoan cysts and trophozoites showed a slightly higher prevalence (11.6%;
n=45; CL95: 8.4–14.8%). Meanwhile, amplification of the 16S rDNA gene detected two species
i.e. Entamoeba dispar (23/388; 5.9%; CL95: 3.6–8.3%) and E. histolytica (11/388; 2.8%; CL95:
1.2–4.5%) and mixed infections with both parasites in only three samples (3/388; 0.8%; CL95:
0.2–2.2%). Entamoeba dispar infection was significantly associated with those employed in
food and domestic services (χ2
4 = 12.879, p = 0.012). However, none of the factors affected
the prevalence of E. histolytica infection. Despite the low prevalence of E. histolytica in
faecal samples of the study cohort, the presence of this pathogenic parasite still poses
potential public health risks and calls for tighter control strategies based on better availability
of chemotherapeutic treatment and accessibility to appropriate health education.
5.Detection of enteroviruses during a 2018 hand, foot and mouth disease outbreak in Malaysia
Lee, M.H.P. ; Chong, Y.M. ; Tay, C.G. ; Koh, M.T. ; Chem, Y.K. ; Noordin, N. ; Jahis, R. ; Sam, I.C. ; Chan, Y.F.
Tropical Biomedicine 2021;38(No.1):150-153
Hand, foot, and mouth disease (HFMD) is a common childhood disease caused by
enteroviruses. In 2018, a HFMD outbreak in Malaysia affected over 76,000 children. In this
study, we used RT-qPCR and CODEHOP PCR to detect the causative agents in 89 clinically
diagnosed HFMD patients in Kuala Lumpur and Selangor. Most (62.9%) of the children were
below 3 years old. PCR with either assay detected enteroviruses in 84.2% (75/89) and CODEHOP
PCR successfully typed 66.7% (50/75) of the enteroviruses. Sequencing of CODEHOP amplicons
showed co-circulation of multiple enteroviruses with coxsackievirus A6 (CV-A6) and A16 as
the predominant serotypes, but not the neurovirulent enterovirus A71. CV-A6 infection was
more common in children less than 12 months old (p=0.01) and was more likely to cause
vesicles in the gluteal area (p=0.01) compared to other enteroviruses. Establishing a robust
identification method during HFMD outbreaks is important for patient management and
public health responses.
6.Molecular detection of Salmonella enterica serovar Typhi by Vi-qPCR
Nik Noorul Shakira Mohamed Shakrin ; Siti Noor Adnalizawati Adnan ; Asmah Hani Abdul Wahab ; R. Pusparani Ramasamy ; Wan Noraini Wan Yussof ; Noorliza Noordin ; Khebir Verashahib ; Rohani Jahis
Malaysian Journal of Microbiology 2018;14(6):483-489
Aims:
To develop a real-time polymerase chain reaction system Vi-qPCR in the detection of Salmonella enterica serovar Typhi (S. Typhi), targeting the vexC gene encoding for Vi antigen (capsular polysaccharide antigen) and to evaluate its sensitivity and specificity performance using pure cultures of S. Typhi and other enteric pathogens.
Methodology and results:
Microbiological, biochemical and serotyping tests were conducted to determine the phenotypic characteristics of S. Typhi and other enteric pathogens in our collection. Primers were designed using Primer3 software and their in-silico specificity were analysed using Basic Local Alignment System Tool (BLAST). Optimisation of PCR annealing temperature was done prior to assessment of sensitivity and specificity performance against artificial serially diluted seeded stools. The primers were found to be 100% specific in the detection of S. Typhi towards 32 tested clinical strains. Verification of gene amplification by comparing the nucleotide sequences against reference genes in the GenBank database revealed high specificity to S. Typhi. Statistical analysis indicates that this method results in 100% sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Moreover, Vi-qPCR allows the detection of S. Typhi as low as 131.4 CFU/g of stool sample.
Conclusion, significance and impact of study
A rapid and sensitive method for detection of Salmonella enterica serovar Typhi (S. Typhi) is desired as a diagnostic tool to improve typhoid management. The Vi-qPCR represent a promising non-invasive diagnostic tool for medical microbiology laboratories as a method for the detection of S. Typhi in both pure culture and stool specimens especially in chronic asymptomatic carriers where shedding of S. Typhi is intermittent and sometimes occurs in low level.